This invention relates to mineral extraction through electro-deposition and more particularly to providing electrical contacts for the cathode and anode plates.
In a typical electro-deposition process used for the refining of many minerals including copper, copper is extracted from the ore using starter sheets large metal sheets made of titanium or stainless steel. These sheets are suspended in tanks containing the copper ore, a 5%-10% solution of sulfuric acid, plus other chemicals.
In Solvent Extraction-Electro Winning (SXEW), the copper is leached out of the copper bearing ore using sulfuric acid. The acid containing the copper drains to a collection system (pumps, pipes), ending up in tanks containing the large metal plates.
Low voltage/high amperage direct current electricity is applied, using lead as the anode, and the titanium/stainless steel plate as the cathode. The copper is electro-deposited (plated) on the metal to a pre-determined time/thickness.
This low voltage/high amperage current is typically communicated using simple contacts. That is, the cathode itself rests on the bar providing the electrical current. Since the electrical power provided is low voltage/high amperage, and because of the environment in which the SXEW exists, often there are shorts or failure to make good electrical contact between the current bar and the electrode. This results in no or limited deposition being performed on that cathode.
A variety of techniques have been developed which attempt to cure this “shorting problem” by assuring that contacts are made. One such technique is described in United States Pat. No. 6,342,136, entitled, “Busbar Construction for Electrolytic Cell” issued to Virtanen et al. On Jan. 29, 2002. In this approach, the gap between the electrodes is variable which allows the cathodes to be moved to obtain proper contact. Unfortunately, this is often labor intensive and results in non-optimal placement of the cathodes within the bath.
It is clear from the foregoing that there is a need for a simple to use mechanism which will assure that proper contact with the cathodes is assured.